The present invention generally relates to securing electrical cord plugs to wall mounted electrical plug receptacles, and more particularly to the use of a support arm attached to the receptacle with a retention element securing the plug to the support arm to resist pulling forces exerted against the plug or cord that would cause the undesirable result of disconnecting the plug from the receptacle.
Electrical plug receptacles are well known to provide access to the main power supply of a building or residence. These receptacles are often mounted in an opening formed in the building wall. Once the electrical receptacle has been mounted in wall, a cover plate is typically secured over the opening so that the only access openings are the exposed receptacles that are approximately flush with the wall surface. Typically, the electrical plug receptacle, commonly called a duplex receptacle outlet has a threaded mounting hole that is approximately located in the center of the receptacle that is between the two electrical plug receptacles, with a screw that mounts in the threaded hole wherein the screw secures the cover plate to the receptacle.
While the previously known electrical plug receptacles permit electrically operated devices to receive the electrical power by merely plugging in an appropriate plug into the receptacle, however, the plug can be easily removed from the receptacle as well. Thus, when the electrical cord extending between the plug and the electrically operated device is pulled upon, either from moving the device, a person tripping over the cord, the inadvertent activities of a child or a pet can cause the cord and hence the plug to be pulled upon. This pulling tension in the cord can easily displace the plug from its receptacle connection resulting in an the undesirable loss of electrical power to the device.
The desire of securing the plug to the receptacle is a well-known problem in the prior art and there have been a number of previously known inventions for maintaining the plug in its inserted position within the receptacle thus protecting against inadvertent removal of the plug from the receptacle. These previously known inventions that attempt to solve the problem of retaining the plug in the receptacle have for the most part, required extensive modifications or specialized construction of the receptacle, cover plate, the plug and cord, or even the receptacle housing that is mounted in a wall. Hence, these modifications or specialized construction tended to not be economically practical due to the additional cost and complexity required to solve the aforementioned problem. Prior art examples would be U.S. Pat. No. 4,702,709 to Santilli that uses a pivotally mounted bracket attached to a special frame piece that mounts against receptacle, or U.S. Pat. No. 5,934,919 to Cross et al. requires a special cover plate that has interlocking channels that attach to a plug retainer. Other examples would be a U.S. Pat. No. 5,299,099 to Archambault that also requires a special cover plate that has raised bars to loop retainer straps through and across the plug for retention, and U.S. Pat. No. 5,989,052 to Fields et al. utilizes another version of a special cover plate that has special interlocking slots that engage a cap that fits over the plug wherein the cap interlocks in to the special cover plate slots.
Another issue with the aforementioned prior art has to do if whether the plug is secured or the cord is secured. A safety issue can exist if only the plug is secured in this situation where a substantial pulling force is experienced by the cord alone with the plug retained against the receptacle results in there being a risk that the cord will disengage from the plug. This disengagement can be quite risky because of the haphazard breaking that may occur of the insulation and wires inside of the insulation in the cord, given the fact that the cord is electrically live which can potentially result in electrocution of an individual, fire or damage to the electrical device itself, not to mention the destruction of the cord and plug assembly. This problem has been identified in the prior art, however, a number of the prior art inventions in this area do in fact only retain the plug, such as Cross et al., Archambault, and Fields et al. Other prior art such as U.S. Pat. No. 5,547,390 to Laherty, U.S. Pat. No. 3,838,383 to Wilbur et al., and U.S. Pat. No. 2,089,665 to Roberts et al. do indeed secure only the cord at a distance from the plug which would generally be desirable given the above information. However, another issue does exist especially related to the inadvertent or accidental removal of the plug from the receptacle by a child or pet, in that the distance of the cord from the plug and cord termination point on the plug to the cord retention point. Given the flexibility of the cord, the plug can still be removed from the receptacle even with the cord retention device securely in place, thus allowing a serious flaw in the ability of the plug and receptacle retention device to effectively prevent inadvertent or accidental removal of the plug from the receptacle causing an undesirable loss of electrical power. In other words, there is no true xe2x80x9clockingxe2x80x9d of the plug to the receptacle given that the plug can still be inadvertently removed from the receptacle thus overriding the retention device.
Still another issue, is the electrical conductivity of the plug and receptacle retention device itself, to maximize safety the retention device should be non conductive. Thus, the retention device should be constructed of non electrical conducting materials to further protect against an inadvertent electrical short circuit in either the plug or the cord being transmitted into the retention device and adding to the risk of electrocution of an individual or fire. In addition, constructing the retention device from resilient materials such as plastic, helps to avoid cutting or nicking damage to the plug and cord further reducing the risk of electrocution or fire. U.S. Pat. No. 2,089,665 to Roberts et al., U.S. Pat. No. 3,960,432 to Wilbur, and U.S. Pat. No. 3,838,383 to Wilbur et al., are all examples of plug and receptacle retention devices that can potentially be electrically conductive by being constructed of metallic materials that also have the undesirable feature of a sharp hard edges that can potentially nick and cut the plug and cord where the retention device comes into contact with the plug and cord.
A final issue with the plug and receptacle retention devices is the ability to retain one plug in a duplex receptacle and not retain another plug in a duplex receptacle, in other words to not have the retention device require all plugs in the receptacle to be retained. A number of the prior art devices force the user to retain the plug in both receptacles of the duplex receptacle. Examples would be U.S. Pat. No. 3,775,729 to Casper and U.S. Pat. No. 6,095,846 to Becerra that do not allow one receptacle out of a duplex receptacle assembly to be freely used by multiple electrical devices necessitating a number of different plugs to be easily used in and out of one of the receptacles while the other receptacle of the duplex receptacle assembly has the plug secured or retained to the other receptacle outlet.
What is needed is an electrical plug retention device that can accommodate the widely varying size differences of plugs and cords, has the ability to retain the cord alone to protect the cord plug interface from separating due to cord pulling tension, is made of non conducting and non cutting or nicking materials, and has the ability to leave one receptacle free and retain a plug in the other receptacle of the duplex receptacle assembly. Also, the retention device should be easy to install, inexpensive, and require no modification to the existing duplex receptacle assembly. In addition, the retention device should be child and pet proof, in other words xe2x80x9clockablexe2x80x9d to prevent the inadvertent or accidental removal of the plug from the receptacle.
It is an object of the present invention to secure or retain an electrical plug to a receptacle for the purpose of preventing an undesirable loss of electrical power to an electrical device.
It is another object of the present invention to provide an electrical plug retainer that can accommodate a wide variety of size differences of plugs and cords.
It is still another object of the present invention to have the capability of retaining the cord alone to protect the cord plug interface from cord pulling damage.
It is yet another object to the present invention to lockably retain the plug in the receptacle to prevent children and pets from inadvertently or accidentally removing the plug from the receptacle.
It is a further object of the present invention for the retainer to be constructed of non conductive material that has no hard or sharp edges to minimize the safety risk from an electrical short circuit or physical damage to the plug or cord.
It is yet further an object of the present invention to allow at least one receptacle to be freely used while another receptacle in the same outlet assembly has the electrical plug retainer in use.
It is still yet another object of the present invention to not require modifications to the existing duplex receptacle assembly and allow for easy installation with minimal or no tools required.
The present invention is an improved electrical plug retainer system that is adapted to lockably secure a plug and cord set assembly that is removably engaged to an electrical receptacle. The electrical plug retainer system protects against accidental removal of the plug and cord set assembly from the receptacle. The electrical plug retainer system includes a support arm that extends from and is supported by the electrical receptacle. The support arm includes a proximal end portion that is adjacent to the receptacle and a distal end portion that is opposite of the proximal end portion of the support arm. The electrical plug retainer system also includes a retention element that is adapted to engage the distal end portion of the support arm, the retention element secures the plug and cord set assembly to the support arm when the retention element is in a locked state. The retention element is removable from the distal end portion of the support arm when it is in an unlocked state. The plug and cord set assembly is lockably secured to the electrical receptacle when the retention element is in a locked state.
These and other objects of the present invention will become more readily appreciated and understood from a consideration of the following detailed description of the exemplary embodiments of the present invention when taken together with the accompanying drawings, in which;